Method for detecting burnt odor from air conditioner, reproducing burnt odor and preparing corresponding burnt odor composition

ABSTRACT

A method that identifies the compounds contributing to a detected burnt odor from an air conditioner artificially reproduces the detected burnt odor, and prepares a corresponding burnt odor composition is provided. Through the analysis method of the present invention, the compounds that contribute to the detected burnt odor from an air conditioner are be identified and quantified. The detected burnt odor is reproduced from a combination of the compounds identified by the analysis method of the present invention. The reproduced burnt odor provides significant data required for development of an apparatus and a method for removing specific odor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2012-0129666, filed on Nov. 15, 2012 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

(a) Technical Field

The present invention relates to a method for detecting a combination of compounds contributing to burnt odor from an air conditioner, a method for reproducing the burnt odor and preparing a corresponding burnt odor composition.

(b) Background Art

Clean air is an essential element for maintaining human health and well-being. Two factors have been known to cause unsatisfactory indoor air quality in an airtight building such as the building itself which produces a substantial amount of air pollutants that need to be removed or diluted and odors generated as a result of human activities.

An air-cooling system lowers interior temperature and optimizes interior environment through air conditioning which changes air temperature, humidity, flow and cleanliness to more favorable conditions. Increasingly, air-cooling systems are being used to improve the standard of living. Although the air-cooling systems have been improved functionally over time, problems remain to be solved in terms of interior air quality. In the past, lowering interior temperature was viewed as one of the most fundamental and important functions of the air-cooling system. However, currently, health-related aspects such as interior air quality and odor may also be regarded as important functions of air-cooling systems. In particular, complaints regarding interior air quality include offensive odor such as burnt odor, foul odor, foot odor, and the like. To solve the odor problem, it may be necessary to analyze the odor-causing substances and understand the fundamental cause of the odor.

Fungal and bacterial metabolites have been known to be the a main cause of odor from an air conditioner, however, it is not still clear regarding the type and the amount of metabolites produced from the microorganisms may remain unclear. Additionally, since it is unclear specifically what compounds cause the offensive odor, it is may be necessary to understand what the type of compounds that contribute to the fish-like smell odor from the air conditioner.

SUMMARY

Numerous complaints are commonly made regarding various offensive odors from an air conditioner (e.g., more than 20 kinds including musty odor). The present invention discloses a method for identifying the compounds that contribute to burnt odor from an air conditioner, collecting offensive-smelling gas from a vehicle, and developing a method for artificially reproducing the burnt odor.

The present invention provides a method for detecting the compounds that contribute to burnt odor from an air conditioner from among various offensive odors emitted from the air conditioner.

The present invention also provides a method for identifying the compounds that contribute to burnt odor from an air conditioner from among various offensive odors emitted from the air conditioner and artificially reproducing the burnt odor using the identified chemical compounds. Additionally, the present invention provides a method of preparing a corresponding a burnt odor composition from the detected burnt odor. The burnt odor composition may also be applicable to any applications where burnt odor is emitted, in addition to the air conditioner.

In one aspect, the present invention provides a burnt odor composition from an air conditioner including one or more compound selected from a group consisting of hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.

In another aspect, the present invention provides a burnt odor composition from an air conditioner including hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane and 2-methylpentane, n-undecane.

In yet another aspect, the present invention provides a method for analyzing the compounds contributing to burnt odor from an air conditioner, including the steps of:

(i) collecting a gas emitted from an air conditioner; and

(ii) analyzing the components of the gas.

In another aspect, the present invention provides a method for preparing a corresponding burnt odor composition from a detected burnt odor, including mixing two or more compounds selected from a group consisting of hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.

Other features and aspects of the present invention will be apparent from the following detailed description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features and advantages of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated in the accompanying drawing which is given hereinbelow by way of illustration only, and thus are not limitative of the invention, and wherein:

FIG. 1 is an exemplary flow chart describing a method for analyzing the compounds contributing to burnt odor according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, combustion, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from the context, all numerical values provided herein are modified by the term “about.”

Hereinafter, reference will now be made in detail to various exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the accompanying claims.

In one aspect, the present invention provides a burnt odor composition from an air conditioner including one or more compound selected from a group consisting of hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane. More specifically, the present invention provides a burnt odor composition from an air conditioner including hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.

The burnt odor composition from an air conditioner may include: about 0.100-80 ppb of hexanal; about 0.1-11 ppb of ethyl-2-methylbutyrate; about 0.0500-70 ppb of heptanal; about 0.1-13 ppb of octanal; about 0.1-14 ppb of decanal; about 0.4-42 ppb of 1,3,5-trimethylbenzene; about 0.3-30 ppb of 1-methoxy-2-propanol; about 0.28-32 ppb of decane; 1-103 ppb of 2-butoxyethanol; about 0.23-27 ppb of ethylbenzene; about 0.03-5 ppb of heptane; about 0.07-9 ppb of 2-methylpentane; and about 0.42-46 ppb of n-undecane.

In another aspect, the present invention provides a method for analyzing the compounds that contribute to burnt odor from an air conditioner, including the steps of:

(i) collecting a gas emitted from an air conditioner; and

(ii) analyzing the components of the gas.

In yet another aspect, the present invention provides a method for analyzing the compounds that contribute to burnt odor from an air conditioner and reproducing the burnt odor, including: evaluating offensive odor; collecting a gas emitted from an air conditioner; analyzing the components of the collected gas; classifying the components; reproducing compositions; performing a multiple test (for at least 5 panelists); selecting the representative composition; and completing the reproduction of the burnt odor composition.

FIG. 1 is an exemplary flow chart describing the method for analyzing the compounds contributing to burnt odor and reproducing the burnt odor.

The burnt odor from an air conditioner of the present invention may be from an air conditioner in an environment including a building, a vehicle, a van, a bus, etc. More specifically, the air conditioner may be an air conditioner used in a vehicle, van or bus.

In an exemplary embodiment of the present invention, the gas in the step (ii) may include hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane. In addition, the concentration of the hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane that contribute to the burnt odor may be measured. The analysis of the components in the step (ii) may be performed by gas chromatography/mass spectrometry (GC/MS), gas chromatography with atomic emission detector (GC/AED), gas chromatography/flame ionization detection/olfactometry (GC/FID/olfactometry) or high-performance liquid chromatography (HPLC), but is not necessarily limited thereto.

Representative examples of the analysis method of the present invention are described hereinbelow. However, the analysis method of the present invention is not limited thereto.

Gas Chromatography

In gas-solid chromatography (GSC), an adsorbent solid powder may be used as the stationary phase. In addition, in gas-liquid chromatography (GLC), a liquid stationary phase coated on a solid support may be used.

A carrier gas maintained at a constant flow rate may be supplied from a sample injection device into a separation column via a pretreatment apparatus and discharged after passing through a detector. The pretreatment apparatus, the sample injection device, the column and the detector may be maintained at predetermined temperatures.

When a gas or a liquid is introduced into the sample injection device, the gas may be carried into the column by the carrier gas and the liquid may be carried into the column by the carrier gas after being heated and evaporated. The components of the sample may be separated in the separation column based on difference in absorption or solubility and may sequentially pass through a mass analyzer disposed at the outlet of the separation column.

The time between the injection of the sample into the separation column until a peak occurrence as a result of detection of a specific component included therein may be called retention time, and the retention time multiplied by the flow rate of the carrier gas may be called retention volume. Qualitative analysis may be performed on the process since the values of the retention time and volume may be different for different components under given experimental conditions. Furthermore, quantitative analysis may be conducted since the peak area or height may be related to the amount of the corresponding component present.

Electron ionization is a conventionally used ionization technique. Neutral sample molecules in gas state are bombarded with high-speed electrons to detach electrons and form molecular ions (cations, M⁺). The minimum energy required to produce the molecular ion (M+) from the neutral molecule (M) may be called ionization energy (IE). The ionization energy of an organic compound is about 8-12 eV (800-1200 kJ/mol⁻¹).

M+e ⁻ →M ⁺+2e ⁻

Among the produced molecular ions, those with high internal energy may be fragmented to form fragment ions. To prevent ion formation as a result of reaction between the produced ion and the neutral molecule, the pressure inside the ionization source should be maintained at 10⁻⁵ torr or lower.

Electron beams emitted from a filament may be accelerated to about 70 eV to obtain standard mass spectrums since they provide high ionization efficiency with little change in mass spectrum. The mass spectrum is the recording of the mass-to-charge ratio (m/z) of the molecular ions and the fragment ions. The mass spectrum of the unknown sample may be compared with the stored standard mass spectrums to identify the substance.

Electric fields and magnetic fields may be utilized alone or in combination to separate the ions according to their mass-to-charge ratio. A sector field analyzer, a quadruple mass analyzer, an ion trap, a time-of-flight analyzer, and the like may be used as a mass analyzer.

High-Performance Liquid Chromatography (HPLC)

The HPLC method may be used to separate nonvolatile substances which may be difficult to analyze by gas chromatography based on their difference in physicochemical interactions with a stationary phase and a liquid mobile phase. This method may be used for qualitative and quantitative analysis of aldehydes in the air. Additionally, in HPLC, the target substances may be separated in the separation column based on their difference in reactivity with the stationary phase and the mobile phase.

When HPLC is employed for analysis of aldehydes existing in the air, a separation column in which a nonpolar stationary phase is chemically bonded to a support may be used. Separation may be achieved depending on difference in reactivity and solubility for the mobile phase and the stationary phase. In general, the method wherein a column containing a nonpolar stationary phase is used and a relatively polar sample eluent is used to separate target substances may be called reversed-phase HPLC.

of the material of the tubing in the HPLC method may be stainless steel, polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), glass, or a similar material. Stainless steel may be advantageous due to being resistant to oxidation and corrosion. However, acid may cause damage and contamination to the tubing. Thus, when stainless steel or the like is used, the tubing should be washed with distilled water after use.

Often, an HPLC detector, capable of measuring absorption in the UV-visible region may be used. When incident light of a particular wavelength is emitted from a light source on the sample in the cell of the UV-visible detector, it may be absorbed by the sample. The detector may generate an electrical signal corresponding to the light absorbance, thus allowing quantitative analysis of the sample.

Hereinafter, the method for detecting the components contributing burnt odor according to the present invention is described. However, the application of the method is not limited to the described components.

Detection of Ammonia

The concentration of ammonia in the air may be measured as follows. After adding a phenol-sodium nitroprusside solution and a sodium hypochlorite solution to a sample solution to be analyzed, ammonia may be analyzed by measuring absorbance of indophenols formed from reaction with ammonium ion.

Detection of Methyl Mercaptan, Hydrogen Sulfide, Dimethyl Sulfide and Dimethyl Disulfide

The concentration of the sulfur compounds in the air may be measured as follows. After sampling using a sample bag, analysis may be performed by cold trap-capillary GC and cold trap-packed column GC.

Cold Trap-Capillary GC and Cold Trap-Packed Column GC

The sulfur compound sample collected in the sample bag may be concentrated in a cold trap device which may be maintained at about −183° C. or below using a refrigerant and may be analyzed by GC after desorption. The measurement procedure may consist of sampling, concentration and sample injection to the separation column. A flame photometric detector (FPD), a pulsed flame photometric detector (PFPD), an atomic emission detector (AED), a sulfur chemiluminescence detector (SCD), a mass spectrometer (MS), and the like capable of selectively detecting trace amount of sulfur compounds with substantial linearity, may be used as a detector.

Electronic Device Cooling Cold Trap-Capillary GC

Sulfur compounds existing in the sample are concentrated at low temperature using a cold trap, desorbed at moderate temperature, and transferred into a syringe pump by the pressure of a carrier gas. The desorption occurs at moderate-to-low temperatures (e.g., about 100° C. or lower), not at high temperatures (e.g., above about 100° C.). The concentrated sample transferred to the syringe pump is injected into the separation column and analyzed by the detector. The cold-trapped sample may also be thermally desorbed and injected into the separation column.

Detection of Triethylamine

The concentration of triethylamine in the air may be measured as follows. After sampling using an impinger and acidic filter paper, analysis may be performed by cold trap-packed column GC and headspace-capillary column GC.

Detection of Acetaldehyde, Propionaldehyde, Butyraldehyde, n-Valeraldehyde and Isovaleraldehyde

For simultaneous measurement of the concentration of acetaldehyde, propionaldehyde, butyraldehyde, n-valeraldehyde and isovaleraldehyde contributing to offensive odor, 2,4-dinitrophenylhydrazone (DNPH) derivatives of the aldehyde compounds may be formed and analyzed by HPLC and GC.

Dinitrophenylhydraziner (DNPH) Derivatization and HPLC/UV

DNPH derivatives formed by reacting carbonyl compounds with 2,4-dinitrophenylhydrazine (DNPH) are extracted with an acetonitrile solvent and analyzed by HPLC using a UV detector at about 360 nm wavelengths.

DNPH Derivatization and GC

DNPH derivatives formed by reacting carbonyl compounds with 2,4-dinitrophenylhydrazine (DNPH) may be extracted with an acetonitrile solvent and analyzed by GC after changing the solvent to ethyl acetate.

HPLC Equipment

The HPLC equipment for sample analysis may include a sample injection device, a pump, a separation column and a detector (UV detector). The separation column may be a reversed-phase column (ODS column) to which a nonpolar adsorbent is coated allowing control of the mobile phase solvent according to the mixing ratio. The sample loop of the injection device may be about 20-100 μL based on the sample concentration.

GC Equipment

A capillary separation column may be used for GC, and a flame ionization detector (FID), a nitrogen phosphorus detector (NPD) or a mass spectrometer may be used as the detector.

Detection of Styrene

Styrene may be sampled at the site boundary. After sampling using a solid sorbent tube, a canister or a sample bag, analysis may be carried out by cold trap-GC and solid-phase microextraction (SPME)-GC.

Detection of Toluene, Xylene, Methyl Ethyl Ketone, Methyl Isobutyl Ketone, Butyl Acetate, Styrene and Isobutyl Alcohol

The concentration of toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, styrene and isobutyl alcohol, which are volatile compounds contributing to offensive odor, in the air may be measured simultaneously.

Toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, styrene and isobutyl alcohol may be specified offensive odor substances. Sampling may be performed at the site boundary. The sample collected using a solid sorbent tube may be analyzed by GC after cold trapping and thermal desorption.

Detection of Propionic Acid, n-Butyric Acid, n-Valeric Acid and Isovaleric Acid

The concentration of the organic acids in the air may be measured as follows. After sampling using an alkaline-impregnated filter or by alkaline solution absorption, the collected sample may be pretreated by the headspace method to evaporate the organic acid components. Then, analysis may be carried out by GC.

In another aspect, the present invention provides a method for preparing a detected burnt odor composition from an air conditioner, including mixing two or more compounds selected from a group consisting of hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.

In another aspect, the present invention provides a method for preparing a detected burnt odor composition from an air conditioner, including mixing hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.

In an exemplary embodiment of the present invention, the method for preparing a detected burnt odor composition from an air conditioner according to the present invention may include mixing: about 0.10-80 ppb of hexanal; about 0.10-11 ppb of ethyl-2-methylbutyrate; about 0.05-70 ppb of heptanal; about 0.10-13 ppb of octanal; about 0.10-14 ppb of decanal; about 0.40-42 ppb of 1,3,5-trimethylbenzene; about 0.30-30 ppb of 1-methoxy-2-propanol; about 0.28-32 ppb of decane; about 1-103 ppb of 2-butoxyethanol; about 0.23-27 ppb of ethylbenzene; about 0.03-5 ppb of heptane; about 0.07-9 ppb of 2-methylpentane; and about 0.42-46 ppb of n-undecane.

EXAMPLES

The present invention will be described in more detail through examples. The following examples are for illustrative purposes only and it will be apparent to those skilled in the art not that the scope of this invention is not limited by the examples.

Example 1 Sensory Test

1) Selection of Vehicle Model

Odor was sampled from the air conditioner of a vehicle model A.

2) Sensory Test Method

i) Three out of the four air conditioner exhausts were sealed hermetically.

ii) For sensory test and gas, the exhaust at the left side of the driver seat was sealed hermetically using a glass tube and a vinyl bag.

iii) The air conditioner was operated at level 2 under internal ventilation condition.

iv) The panelist was asked to smell the sample in the glass tube and evaluate the intensity and type of odor.

Table 1 describes the level of odor according to intensity which was used as the standard of sensory test and evaluation after preparation of the mixtures for reproducing the detected odor in Examples 3 and 4.

TABLE 1 Odor intensity Level of odor 5 Irritating and intense odor 4 Strong odor 3 Weak but easily perceived odor 2 Perceived but slight odor 1 Almost unperceived odor 0 No odor

Example 2 Sampling Procedure

1) Selection of Vehicle Model

Sample was taken from the same vehicle as in Example 1.

2) Sensory Test Method

i) Three out of the four air conditioner exhausts were sealed hermetically.

ii) The exhaust at the left side of the driver seat was sealed hermetically using a glass tube and a vinyl bag.

iii) The opening of a 10-L PE sample bag was connected to the glass tube.

iv) The air conditioner was operated at level 2 under internal ventilation condition and gas sample was taken.

Example 3 Sample Analysis

The sample taken in Example 2 was analyzed by absorption spectrophotometry, headspace-gas chromatography with flame ionization detector (HS-GC/FID), gas chromatography with flame photometric detector (GC/FPD), high-pressure liquid chromatography with ultraviolet detector (HPLC/UV), gas chromatography/mass spectrometry (GC/MSD) and headspace-gas chromatography/mass spectrometry (HS-GC/MS).

Table 2 shows the result of detecting compounds contributing to offensive odor from the sample.

TABLE 2 Concentration Components (ppb) Acetaldehyde 25.1 Valeraldehyde 4.8 Toluene 57.7 m,p-Xylene 17.9 o-Xylene 8.6 Styrene 0.5 Methyl ethyl ketone 0.7 Methyl isobutyl ketone 4 Butyl acetate 10.9 Isobutyl alcohol 2.4 2-Heptanone, 7,7,7-trichloro- 1.2 Silane, methyl- 1.2 1,4-Pentadiene 0.5 Hexane, 3,3,4,4-tetrafluoro- 1.6 Pentane, 2-methyl- 0.8 Propane, 1-chloro-2-methyl- 0.6 Oxetane, 2,3,4-trimethyl-, (2.alpha.,3.a 8.9 2-Propanol, 1-methoxy- 2.9 Sulfide, allyl methyl 0.8 Heptane 0.5 Methyl isobutyl ketone (MIBK), 4-methyl- 1.3 Hexanal 0.9 Acetic acid, butyl ester 5.7 Heptane, 2,4-dimethyl- 0.4 Cyclotrisiloxane, hexamethyl- 1.4 Butanoic acid, 2-methyl-, ethyl ester 1.1 1-Methoxy-2-propyl acetate 4.6 Ethylbenzene 2.6 Octane, 4-methyl- 0.2 Heptanal 0.7 Ethanol, 2-butoxy- 10.1 Decane, 2,5,6-trimethyl- 1.2 Hexanoic acid, methyl ester 0.6 2-Pentanol, 4,4-dimethyl- 0.5 n-Propylbenzene 1.0 Benzene, 1,2,3-trimethyl- 4.0 Propanoic acid, 3-ethoxy-, ethyl ester 1.2 Benzene, 1-ethyl-2-methyl- 1.9 Pentanoic acid, 4-methyl-, ethyl ester 1.3 Octanal 1.2 Benzene, 1,2,3-trimethyl- 9 Cyclotetrasiloxane, octamethyl- 1 Decane 3.0 Cyclohexene, 1-methyl-5-(1-methylethenyl 2.3 2-(1-Hydroxyethyl)hydroxymethylbenzene 1.4 Hydroxylamine, O-decyl- 1.3 Benzene, 4-ethyl-1,2-dimethyl- 1.1 Nonanal 5.6 2-Propenoic acid, tridecyl ester 0.8 Undecane 4.5 Decane, 2,4,6-trimethyl- 1.4 Benzene, 1,2,4,5-tetramethyl- 2.1 p-Trimethylsilyloxyphenyl-(trimethylsilyl 14.5 3-Hydroxymandelic acid, ethyl ester, di- 0.1 Cyclohexanol, 5-methyl-2-(1-methylethyl) 0.8 Decanal 1.3 4-(Prop-2-enoyloxy)octane 0.3 Trisiloxane, 1,1,1,5,5,5-hexamethyl-3,3- 0.9 Pentadecane 1.1 Silane, dimethyl(dimethyl(dimethyl(2-iso 36.3 Tridecane 1.7 3-Isopropoxy-1,1,1,7,7,7-hexamethyl-3,5, 2.8

Example 4 Preparation of Burnt Odor Composition

A burnt odor composition was prepared by mixing hexanal, ethyl-2-methylbutyrate, heptanal, octanal, dec anal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane according to the compositions described in Table 3.

TABLE 3 First standard gas Second standard gas Standard gas for dilution Bag Bag Bag Volume volume Conc. Volume volume Conc. Volume volume Conc. Components M.W. Density (mL) (L) (ppm) (mL) (L) (ppb) (mL) (L) (ppb) Hexanal 100.16 0.82 1.0 3.0 61.129 1.0 3.0 20.4 20.4 6.0 2.0 Ethyl 130.18 0.87 1.0 3.0 49.900 1.0 3.0 16.6 16.6 7.0 2.3 2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester) Heptanal 114.19 0.82 1.0 3.0 53.618 1.0 3.0 17.9 17.9 11.0 3.7 Octanal 128.21 0.82 1.0 3.0 47.755 1.0 3.0 15.9 15.9 17.0 5.7 Decanal 158.28 0.83 1.0 3.0 39.154 1.0 3.0 13.1 13.1 24.0 8.0 1,3,5-Trimethylbenzene 120.20 0.86 2.0 6.0 53.671 1.0 3.0 17.9 17.9 27.0 9.0 1-Methoxy- 90.12 0.92 2.0 6.0 76.224 1.0 3.0 25.4 25.4 30.0 10.0 2-propanol Decane 142.28 0.73 2.0 6.0 38.309 1.0 3.0 12.8 12.8 36.0 12.0 2- 118.18 0.90 2.0 6.0 57.052 1.0 3.0 19.0 19.0 38.0 12.7 Butoxyethanol Ethylbenzene 106.17 0.87 2.0 6.0 61.185 1.0 3.0 20.4 20.4 40.0 13.3 Heptane 100.21 0.68 2.0 6.0 50.965 1.0 3.0 17.0 17.0 42.0 14.0 2-Methylpentane, 86.18 0.65 2.0 6.0 56.576 1.0 3.0 18.9 18.9 25.0 8.3 99% n-Undecane, 156.31 0.74 2.0 6.0 35.349 1.0 3.0 11.8 11.8 25.0 8.3 99%

The odor of the samples obtained from the air conditioner of the vehicle model A was burnt odor of intensity 3-4, as described in Table 4.

The odor of the burnt odor composition prepared from a combination of the aforementioned components was also burnt odor of intensity 3-4, similar to that from the air conditioner.

TABLE 4 Odor from vehicle air Intensity 3-4 conditioner Characteristic Burnt odor/smoky odor Burnt odor composition Intensity 3-4 prepared from detected Characteristic Burnt odor compounds Causative substance Hydrocarbons Note Intensity Similar Reproducibility Reproducible

The features and advantages of the present disclosure may be summarized as follows.

(i) Through the analysis method of the present invention, the compounds that contribute to the detected burnt odor from an air conditioner may be identified and quantified;

(ii) The burnt odor may be reproduced from a combination of the compounds identified by the analysis method of the present invention; and

(iii) The reproduced burnt odor may provide significant data required for development of an apparatus and a method for removing specific odor.

The present invention has been described in detail with reference to exemplary embodiments thereof. However, it will be appreciated by those skilled in the art that various changes and modifications may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the accompanying claims and their equivalents. 

What is claimed is:
 1. A detected burnt odor composition from an air conditioner comprising one or more compound selected from a group consisting of hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.
 2. A detected burnt odor composition from an air conditioner comprising hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.
 3. The detected burnt odor composition from an air conditioner according to claim 1, further comprises: 0.10-80 ppb of hexanal; 0.10-11 ppb of ethyl-2-methylbutyrate; 0.05-70 ppb of heptanal; 0.10-13 ppb of octanal; 0.10-14 ppb of decanal; 0.40-42 ppb of 1,3,5-trimethylbenzene; 0.30-30 ppb of 1-methoxy-2-propanol; 0.28-32 ppb of decane; 1-103 ppb of 2-butoxyethanol; 0.23-27 ppb of ethylbenzene; 0.03-5 ppb of heptane; 0.07-9 ppb of 2-methylpentane; and 0.42-46 ppb of n-undecane.
 4. The detected burnt odor composition according to claim 2, wherein the composition may be applied to vehicles including hybrid vehicles, electric vehicles, combustion, and fuel cell vehicles.
 5. A method for analyzing the compounds contributing to burnt odor from an air conditioner, comprising: collecting a gas emitted from an air conditioner; and analyzing the components of the gas.
 6. The method according to claim 5, wherein the air conditioner is a vehicle air conditioner.
 7. The method according to claim 5, wherein the gas comprises hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.
 8. The method according to claim 7, wherein the concentration of the hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane is measured.
 9. The method according to claim 5, wherein the analysis of the components is performed by gas chromatography/mass spectrometry (GC/MS), gas chromatography with atomic emission detector (GC/AED), gas chromatography/flame ionization detection/olfactometry (GC/FID/olfactometry) or high-performance liquid chromatography (HPLC).
 10. A method for preparing a detected burnt odor composition from an air conditioner, comprising mixing two or more compounds selected from a group consisting of hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.
 11. A method for preparing a detected burnt odor composition from an air conditioner, comprising mixing hexanal, ethyl-2-methylbutyrate (butanoic acid, 2-methyl-, ethyl ester), heptanal, octanal, decanal, 1,3,5-trimethylbenzene, 1-methoxy-2-propanol, decane, 2-butoxyethanol, ethylbenzene, heptane, 2-methylpentane and n-undecane.
 12. The method according to claim 10, further comprises mixing: 0.10-80 ppb of hexanal; 0.10-11 ppb of ethyl-2-methylbutyrate; 0.05-70 ppb of heptanal; 0.10-13 ppb of octanal; 0.10-14 ppb of decanal; 0.40-42 ppb of 1,3,5-trimethylbenzene; 0.30-30 ppb of 1-methoxy-2-propanol; 0.28-32 ppb of decane; 1-103 ppb of 2-butoxyethanol; 0.23-27 ppb of ethylbenzene; 0.03-5 ppb of heptane; 0.07-9 ppb of 2-methylpentane; and 0.42-46 ppb of n-undecane.
 13. The method according to claim 10, wherein the method may be applied to vehicles including hybrid vehicles, electric vehicles, combustion, and fuel cell vehicles. 